Low pressure tyre warning

The car's on the move now, but the exterior temp is still below 3 degrees (it's been between 1-2 degrees), but the pressures are now aOK.

Screenshot_20250104-150722.png

Shrug.....
 
securespark said:
Very interesting thread. We haven't had an issue with tyre pressures on our 23 phase 2 Trophy LR until recently.

But it's always the rear NS. Until today.

Mrs S has gone to a footy match with brother and father and I am (as ever) confined to bed with broken ankle. But I did my weekly status check. For the first time ever two tyre pressure warnings came up, but get this:

View attachment 33663

How can the system read exactly the same pressure for the rears as the fronts but flag them up as low? That I just don't compute, and obviously His Lordship (our name for the car!) doesn't, either.

As I said, the N/S/R normally pops up as low when it's cold, but it soon reads OK after a bit of driving. I guess today (in the NW where we are and the Midlands where the match is) it is very cold, so maybe the low pressure readings won't disappear with driving.

I've read what others say about ignoring the MG advice and putting 2.6 or 7 in each corner. Is that the solution here?
Click to expand...

2.7 0r 2.8 will improve your m/KWh and prevent alerts.

Probably the front are 2.38 and the rears 2.42 or something and the alert is at 2.39 - without the extra digits visible, it has to be some sort of internal rounding thing. Some displays changed to KPa and that has the extra decimal place which is useful.
 
Last Thursday we had a warm day at 8°C. Back from the service they deflated them so I put them back on 2.6 and 2.7 (which is 2.7 and 2.8 in the car).
Now that temperature has dropped to 0°C and snow is coming, the sensor pressure dropped to 2.5 and 2.6 (front/rear).
 
My car came with 2.8 from the dealer, and they go up to 3.0 when driving long enough. I’ve always preferred 2.7-2.8 anyway, I like a firm tyre.

In the times when petrol was cheap a lot of manufacturers would set their recommended pressures lower so the tyres would flex more and they would say “look how comfortable our vehicle drives!”. Then petrol got expensive and they increased their recommended pressures and started saying “look at how economical our vehicle drives!”

Rule of thumb is 36 psi (2.48 bar) is best for your tyre, any deviation up or down is down to what you prefer (comfort or efficiency) but of course now with tpms settings a manufacturer could push you in a certain direction.

If you really want the best pressure for your tyre on your particular set up, it should be inflated to a pressure that does not increase by more than 5 psi (0.34 bar) when the tyre is warmed up. Any increase above this indicates the air inside is warming up excessively because the tyre is flexing too much.
 
securespark said:
The car's on the move now, but the exterior temp is still below 3 degrees (it's been between 1-2 degrees), but the pressures are now aOK.

View attachment 33676
Shrug.....
Click to expand...
That's because the car is now moving and the pressures have increased just enough to take them above the trigger threshold due to the friction creating a bit of heat.

Just pump all of them up to 2.5/2.6 bar and you won't get any more warnings.
 
Is anyone else having TMPS faults now it’s freezing cold. It’s happening on my 2 rear tyres but come afternoon there’s no issue. Only taken delivery of the car just over a month ago?
 
Checked and the pressures are ......... ?

Should be 2.55 bar (37 psi) minimum when cold.

Of course it's entirely possible you have a TPMS fault, but unless you give us more detail we can't help. 🤷‍♂️
 
37 was what I was getting when I checked half an hour ago, I’ll allow some extra time in the morning if the error comes up again and go to the petrol garage and check then. Cheers for the advice
 
Or reset the TPMS first thing in the morning when the tyres are cold and at their lowest pressures.
 

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